Effects of high and low ligation on survival in patients operated for colorectal cancer.

In spite of numerous studies on the subject, it is still unclear whether or not high ligation of the inferior mesenteric artery (at about 1 cm from its origin) improves the 5-year survival rate in patients operated on for colorectal cancer in comparison to low ligation (ligation below the origin of the left colic artery). From February 2000 to November 2001 40 patients with cancer of the colic segment between the descending sigmoid junction and the low rectum underwent surgical colorectal resection and low ligation of the inferior mesenteric artery. At the end of 5 years of observation we report a survival rate of 70% which is not very far from the value reported in the literature. In our study, the incidence of lymph-node metastases, inexistent in patients with T1 grading increases with the increase in the TNM T grading but does not depend on the location of the cancer. In our patients age below 65 years was a negative prognostic indicator because colorectal tumours in patients of that age are associated with a higher incidence of lymph-node metastases. On the basis of the data we obtained, it is also evident that the 5-year survival rate decreases in proportion to the increase in the distance of the lymph-node metastases from the mesenteric margin of the colon. In conclusion, in the treatment of cancers located between the descending sigmoid junction and the low rectum, we prefer to execute a low ligation of the inferior mesenteric artery because it exposes the patient to a lower risk of intra- and postoperative complications and also because several authors have demonstrated that high ligation with removal of lymph nodes at the origin of the artery for colorectal cancer does not improve the 5-year survival rate.